I wondered how long would you expect out of muffler. My Berklee BSO655 has rotted out the inside perforated tube. resulting in muffler blocking with glass wool causing back fire and fine fiber glass all over back of car. Its Just under 3 years old outside of muffler perfect. I wonder if its because of Dual fuel?
I put stock muffler back on and fuel consumption has improved but maybe little less power.:eeek:

Depends if has been used for mainly short or long trips. Lots of short trips will tend to rot a muffler a lot faster.

Mine did this about three years after install.

I do two short trips per day, very rarely anything more than 5 mins. Car just reaches operating temperature when I turn it off. Exhaust doesn't get hot enough to evaporate moisture and the muffler just rusts out.

Luckily I managed to buy two more Berklees from TreeAdeyMan, I will just keep swapping them over when they die.

Pity the don't make them in a stainless version.

When the last one dies I will look at a stainless equivalent.